


Parallelogram

by blancafic



Category: Agents of S.H.I.E.L.D. (TV)
Genre: Alternate Universe, Established Relationship, F/M, FitzSimmonsing, Mutual Pining (sort of), Parallel Universes, Pining, Post-Season/Series 06
Language: English
Status: Completed
Published: 2019-08-08
Updated: 2019-09-12
Packaged: 2020-08-13 06:16:13
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 4
Words: 14,307
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/20169520
Author URL: https://archiveofourown.org/users/blancafic/pseuds/blancafic
Summary: Jemma is visited by a mysterious stranger who claims he knows her and asks for her help. Any logical person would send him packing, but there's something about him that makes her want to trust him.





	1. Another Jemma

**Author's Note:**

> This began as a drabble I posted for AosFicNet's [July Drabble Challenge](https://archiveofourown.org/works/19602253/chapters/46508950). I had some requests to expand it into a full story and I got inspired, so here we are. 
> 
> Special thank you to LibbyWeasley for being the best cheerleader and beta ever and helping my find my way through this.

The moment that changed Jemma Simmons’ life came late at night, while she was at home in her childhood bedroom, half-heartedly skimming an old biology textbook and avoiding everyone she knew. The timing couldn’t have been better. Perhaps, on some level, she’d known even then that something important was about to happen. Her life was already in shambles, so things could only improve from there.

Unable to sleep, she’d stayed up reading until well past midnight. She was just starting to notice the words blurring on the page when she heard voices downstairs. Her dad was speaking with someone at the front door. Which was odd, since she could have sworn her parents had gone to bed hours ago. She couldn’t hear what they were saying, but it sounded like the man was in need of some assistance. Drawn by the voices and her own curiosity, she tiptoed down the stairs to get a better look.

Her father stood in the open doorway with a puzzled expression on his face. “Are you sure you have the right Jemma Simmons?” he said.

Hearing her name, she crept even closer.

“I’m absolutely sure,” the man insisted. She couldn’t see him beyond the threshold, but she detected a distinctive Scottish accent in his voice. He sounded like he was at the end of his rope. “Please, Mr. Simmons. I’ve come a very, very long way to speak to your daughter. Five minutes. That’s all I ask.”

“Hold on a tic,” her dad said, closing the door on the man even as he continued to plead for access. She could still hear him swearing on the other side.

“Dad?” Jemma said, coming around the corner as if she’d just arrived. “Who was that?”

“No idea. Wouldn’t give his name, just asked to speak to you. But I didn’t think you wanted to see anyone right now. And it is quite late.”

“What did he want?”

“He didn’t say. Wait, he’s not the reason you--”

She cut him off before he had a chance to finish.

“No. For the last time, it was for me. Just me. There was no external reason, so stop looking for one.”

“If you say so, sweetheart. But you can understand my confusion, given the circumstances.” She huffed and his face softened. “So do you want me to send him away or not?”

“It’s alright, dad. I’ll handle it. Go back to bed.”

“Good night, Jemma love. And do be careful. He had a sort of wild look in his eyes. I didn’t care for it.”

He kissed her on the forehead and padded back upstairs in his slippers.

She opened the door again and found a disheveled stranger about her age pacing on the stoop. He was wearing an untucked button-down with the sleeves rolled up over dress slacks. His face was rough with stubble and his sandy, curl-inclined hair stuck out in all directions. He was talking to himself and gesticulating wildly with his hands. When he turned and saw her, though, his deep scowl transformed into an expression of immense relief. It made him look at least five years younger and much less threatening. In fact, she dared to admit, he looked objectively handsome.

“Jemma!” he exclaimed with a strange familiarity, though she was positive she’d never seen him before in her life. She would have remembered. “Oh thank god.”

She ducked to avoid being swept up in his arms. “Sorry, do I know you?”

His face fell again as his arms dropped to his sides. “Apparently not. Okay. Well. I suspected this was a possibility when your dad didn’t recognize me. And by the look on your face, you don’t either. So that’s not great. Stupid bloody universe.”

He kicked a potted topiary, almost toppling it over.

“Hey, don’t take it out on the porch plants,” she chided. At least he had the decency to look regretful over the outburst. “Just tell me who you are and what you’re doing at my door after midnight, acting like you know me.”

“How to explain,” he said, more to himself than to her. He went back to pacing, rubbing his hands over each other as he crossed from one end of the porch to the other. “Okay. At least you exist here. That’s something. I mean, you’re still Jemma Simmons, right? If anyone could understand the situation, it would be you. Christ, you look so much like her, though. Which is really freaking me out.”

Cute though he might be, he sounded completely mental. She knew the logical thing to do was to turn around, go back inside, and never look back. But something kept her there. “Slow down. You’re not making any sense.”

He froze for a second, then shook his head, chucking at some private joke. “You even sound like her.”

"Did Colin put you up to this?"

He scrunched up his face in distaste and said, "Who's Colin?" but she barreled right on past him.

"Sending some random stranger to my house late at night to harass me. That would be a new low, even for him."

"No, no one sent me. I came on my own. I don't even know this Colin person." He spat the name as if it were curse.

“Okay, have it your way. But I think I’ve been more than patient with this sudden intrusion, so either you explain to me exactly what’s going on right now or I’m calling the police.”

It was an empty threat, but he didn’t know that. Her words seemed to snap him out of his manic state and he turned his focus back to her.

“Worth a shot, I suppose,” He licked his lips and closed the distance between them. Though the porch was dim, she could see an intriguing circle of blue around the wide pupils of his eyes. “Okay, my name is Leopold Fitz. I’m an engineer. Does that ring any bells?”

“No. Sorry, Leopold.”

He winced and sharply corrected her. “It’s Fitz.” But then he seemed to regret the harshness of his tone and continued in a gentler voice. “Please. Just Fitz. So, uh, have you by any chance ever heard of the multiverse theory?”

“Of course. It states that there are an infinite number of universes existing in parallel with each other.”

The corner of his mouth turned upward at that. He met her eyes and there was a strange fondness in there that made her legs go wobbly.

“Exactly. Good. So every decision we make creates a new timeline, which then branches off into more timelines, and so on and so on, ad infinitum.”

Why was he explaining things she already understood? “Yes, I know the theory. What about it?”

“Well, imagine that you could travel between universes.” He gestured with his fingers, making an arcing motion from one hand to another. “See the consequences of those changes over time. Some things would be the same, some things different.”

She considered it. “I suppose it could be possible. But it’s never been proven.”

“What if I told you I’m the proof?” Fitz said.

“Hold on. So you’re saying . . .”

“I come from a parallel universe. One where you and I . . . let’s just say we know each other.”

His sincere countenance showed no trace of a lie, but it couldn’t hurt to test him. “If you know me so well, or some version of me, then what’s my favorite color?”

She crossed her arms defiantly, waiting for an answer.

“Well. I don’t know about you, but the Jemma in my universe tells everyone her favorite color is indigo, when I know for a fact it’s actually pink. Upstairs, your bedroom is yellow with butterflies and a Jane Goodall poster on the wall. And you keep all your worries and fears locked up in a little music box inside your mind. Which is really unhealthy, by the way, so maybe you should see someone about that.”

Her jaw fell open. He was right on all counts. It was all too detailed for him to have made it up, and too personal for him to have known those things any other way. She'd never told a single soul about the music box. Which left her with only one choice. She turned around and closed the door. Then came back to face him.

“Okay, I believe you.”

“I know it sounds--” he began, ready to dive further into his explanation before registering her words. “Wait. You believe me?”

She had a feeling he wasn’t telling her the whole story, but it did make a kind of sense. “It explains a lot, actually.”

He gave her a genuine smile and she tried to ignore the way it made her stomach bottom out. They stood there for a moment, wordlessly taking in each other. It was the easiest, most comfortable silence she’d ever felt with anyone. The feeling wasn’t just a feeling any more; she knew beyond a shadow of a doubt there was a _lot_ he wasn’t telling her.

“Do you trust me?” he asked suddenly.

She blinked. Though she’d never met the man before there was something in his eyes that made her feel instantly at ease. “Yes,” she said, without hesitation.

“Good. Because my Jemma is waiting for me in another universe and I need your help to get back to her.”

She couldn’t help but envy that other version of herself. Her life must have been considerably more interesting if this man was a part of it. He seemed so desperate, she knew she had no choice but to help him.

“What can I do?”


	2. Fitz

**Summary for the Chapter:**

> Fitz and Jemma work together to get him back to his universe, but the closer they get, the more their confused and inconvenient feelings come to the surface.

**Notes for the Chapter:**

> Once again, LibbyWeasley was a fantastic beta and a massive help in the writing process for this chapter. She gave me the perfect suggestion for Jemma's choice of time-travel destination, and so much more.

As they sat together on the porch steps making plans, Fitz had to keep reminding himself that this Jemma was not his wife. They had an easy rapport and the resemblance was uncanny, but in her eyes he saw a stranger’s soul. She had an unfamiliar sort of melancholy about her, not born of loss and tragedy and the weariness of having to save the world one too many times, just an ordinary kind of sadness. Or maybe loneliness, but he was probably just projecting. She must have felt some connection to him, though. Why else would she be so willing to trust him and help him get home?

“I need a place to work. A lab or a workshop,” he explained. “Somewhere quiet with lots of power. And tools and equipment to fabricate the parts.”

“We could try the university,” she suggested. “I work there. I know of a lab that should have everything you need, but . . . hmm.”

She looked away from him and stared out into the dark street. The porch light above them lit her face in profile, giving her an ethereal glow. When she sighed deeply he had to sit on his hands to avoid reaching out to her.

“What? What is it?”

She tucked her hair back behind her ear, a nervous tic he recognized. “It’s just that my ex-boyfriend . . . well, ex-fiancé . . . he works there too. Much higher up the food chain than me. He’s on the board of the Energy Institute, so I’m sure he could get us into their lab. Although . . . I don’t even know if he’ll take my call.”

“I’m sorry,” he said, meaning it. The idea of her being with someone else left a bad taste in his mouth, but he still hated to see her hurt. “Did it end badly?”

Her laugh was brittle. “You could say that. The wedding was supposed to be this Saturday, but I called it off a week ago. Hid away here, took a leave of absence from work, wouldn’t see or talk to anyone. At least, not until you showed up.”

She gave him a weak smile. Now he understood where that sadness came from. He wanted to know more, but she didn’t elaborate further. So he returned her smile with an encouraging one of his own.

“I don’t want you to do anything that makes you uncomfortable,” he said. “We’ll figure something out.”

“And then what? Once we secure the lab and the equipment, what’s the plan?”

“Then we’re going to build a quantum jump drive from scratch.”

He wasn’t entirely sure it could be done, but didn’t want to say so out loud. The one they’d built in his world obviously didn’t work properly. He’d let Jemma choose the target time and place for their first test, and wasn’t at all surprised to find that it hadn’t changed since their Academy days, when they used to talk about what they’d do if they had access to a TARDIS. Now, they sort of did. They’d been aiming for King’s College in London, 1951, where Rosalind Franklin was in the process of producing the world’s first X-ray images of DNA. Instead, the portal sucked him in and spit him out in the right place, but the wrong universe. On the same day he’d left.

Fortunately, this world didn’t seem that different from his own. Considering all the potential places he might have landed, it could have been much, much worse. He knew with an aching, first-hand certainty how small changes in history could make a world of difference. Quite literally. Other than a few details he’d caught while skimming a London newspaper, though, everything appeared relatively normal so far. No airships in the sky. No dystopian overlords. No Hydra. 

Once he realized what had happened, his first instinct — as always — was to turn to Jemma to help make sense of it all. With no way to contact this world’s version of her or the team, he figured his best bet was to try her parents for an address or a phone number, assuming they were still alive and living in the same place. So he exchanged the dollars in his wallet for pounds and bought a one-way ticket to Sheffield. The gamble paid off even better than he could have hoped when he’d found Jemma herself staying there. It didn’t matter that she didn’t know him. He knew her well enough to win her over. Maybe this new universe was actually on his side for a change. Wouldn’t that be nice?

Seeing as there was nothing more they could do until daylight, Fitz decided to take his leave. Jemma invited him to spend what was left of the night on her parents’ couch, but he felt more comfortable checking into a nearby hotel. Still, she insisted on driving him there and helping him get checked in. Once she was sure his accommodations were settled for the night, she offered him an awkward but warm handshake and promised to come back to meet him for breakfast and brainstorming in the morning. He didn’t get much sleep that night, but when he eventually drifted off he dreamed of his own Jemma and the life waiting for him back in their world.

The next morning she met him bright and early as planned, with a fresh change of clothes she’d snuck out her father’s closet. Together, over scones and tea in the hotel’s small cafe, they came up with a cover story for him that avoided any direct contact between her and her former fiancé. Fitz would pose as a visiting researcher from the University of Glasgow working on a top secret project for the government that required the superior facilities of the Energy Institute. She told him exactly who to contact and coached him on what to say to the right people. 

It all went fairly smoothly, even the part where he’d had to talk to the idiot who’d let Jemma Simmons get away — Dr. Colin Jenkins, Director of Research and Development. Fitz was inclined to dislike him even before he picked up the phone, but their brief conversation certainly didn’t improve his opinion any. Jemma had advised him to use a combination of scientific knowledge and flattery to win him over, and the egotistic prat ate it up. Fitz couldn’t help feeling Jemma had made the right decision backing out of that engagement. By late morning, Fitz had been granted complete access to the lab and all of its equipment.

On the way to the lab he noticed her knee bouncing under the steering wheel. 

“I’m sorry I’m making you go back to work before you’re ready,” he said. “If you want, you can wait in the car while I get set up and we can sneak you in later.”

“It’s not that,” she said, glancing over at him quickly before turning her eyes back to the road. “I mean, I’m not looking forward to the looks of judgement and pity, but I was just thinking, what if we don’t solve this? What if you’re stuck here?”

“We’ll solve it,” he said, with more conviction than he felt. “I mean, we do have three doctorates between us, right? We should be able to figure this out.”

She scoffed. “Not unless you don’t have any yourself. Which I highly doubt.”

“Really? Three PhDs?” She nodded and he whistled in appreciation. “My . . . I mean, the Jemma in my universe only had two.”

He thought about how much Jemma would hate knowing that there was another version of her out there who’d earned one more advanced degree than she had, but decided to keep that to himself.

“Technically, two PhDs and an MD. After I dropped out of the Academy I came back home and went to medical school. I figured even if I couldn’t save the world in a big way I could still find small ways to help.”

“So you never joined S.H.I.E.L.D.?”

“Lord, no. I’m a clinical pathologist. I study and track rare diseases, with a specialty in pathogens of unknown origin. I shouldn’t be telling you this, and you probably won’t believe me anyway, but I’ve even encountered some that turned out to be _not of this world_.”

She articulated the last part in an exaggerated whisper and gave him a knowing look that made him want to laugh. Or kiss her. It wasn’t the first time he’d had to resist that particular urge. It only made him miss his Jemma all the more.

“But why did you leave the Academy in the first place?” She started fidgeting again and he wondered if he’d hit a nerve. “Sorry. If that’s too personal.“

“No, it’s fine,” she said. “I was the youngest person there and I never really got on with anyone else in the program. The professors tried to engage me, but I was always a bit—“

He nodded his head in understanding and finished for her: “Lonely.”

At the same time, she finished for herself: “Bored.”

He jerked his head back in surprise. Why was he a little disappointed by that? It made perfect sense. She was always miles ahead of the curriculum. And without him there to challenge her and provide some competition he could easily imagine her interest waning. Which led to another question, one she likely couldn’t answer. Why hadn’t his counterpart been at the Academy to befriend her?

Before he could pursue that line of thinking, though, they arrived at their destination. They quickly went over his cover story in the car, then entered the university building together and wound their way through the corridors to the lab. No one stopped them on the way. He assured Jemma they wouldn’t, as long as they blended in and looked like they knew where they were going. It was a well-worn spy tactic, but it worked. 

Once they’d cleared out the lab techs — he only had to raise his voice a little, barely a shout, really — they got to work. 

At one point during the night before he’d given up tossing and turning and had drawn up plans for the jump drive on the back of a room service menu. The specs of the original drive were still fresh in his mind. They’d had to pull it apart completely, reverse engineer bits and pieces, and find workarounds for the alien technology they didn’t understand. But thanks to those efforts he was able to recreate some fairly accurate sketches for a new one. When he unfolded the menu and showed the designs to Jemma she examined them carefully, a look of concentration appearing on her face that he’d seen thousands of times before. It was eerie. She even had the same little wrinkle between her eyebrows.

The two of them spent the entire day and the next fabricating the parts and fitting them together, falling into an effortless rhythm, side by side. To Fitz, it was like slipping on a comfortable old pair of shoes. He was grateful for the work, to have a project to concentrate on instead of his poor, confused heart, which could scarcely tell the difference between the love of his life and this stranger next to him. His head was much clearer on the issue. Yet he kept wondering what was going through hers. And why she hadn’t slammed the door on him the minute he said “parallel universe.”

It was three days before he got his answer.

He was on his back on the floor underneath the machine when he heard her speak. Her voice sounded small and far away, a marked difference from the confident scientist he’d come to know.

“Fitz, can I ask you something?”

“Sure,” he said, tapping a spanner against the base frame. The fusion matrix was sputtering and he was trying to isolate the problem.

“You and the other Jemma. In your world. You’re more than just friends, aren’t you?” She stated it more like a fact than a question.

“Uh.” He stopped working and slid himself out from under the drive. She stood over him, biting her lip and shifting her weight from one foot to the other. 

“It’s just, you keep giving me these looks. I’m not even sure if you know you’re doing it. It’s . . . quite a lot.”

“Oh god, I’m so sorry,” he said, scrambling to his feet. “I didn’t mean—”

“No,” she cut him off and put her hands up. “It’s okay—”

“Still, I shouldn’t—”

“Really. I don’t mind—”

“I know it’s not fair—” 

“Stop,” she said. And he did. “You don’t have to explain. I can tell how much you miss her.”

All the air left his lungs in one, long, relieved sigh. It felt good to finally let it out. “I really do. I should have told you up front, but I wasn’t sure how it would sound on top of everything else. Never was any good at hiding it, though. So, yes. The Jemma in my world, she isn’t just a friend or a partner or a colleague to me. She’s my wife. And I love her more than anything.”

She took the tiniest of steps back from him. “Oh. Wow. Um. Congratulations? No, that’s not the right word. Best wishes? I’m really happy for you. Truly. She’s . . . well, you’re both . . . very lucky.”

She was rambling in the most adorable fashion, but her eyes were glassy, her smile too wide. That’s when it hit him. She had a crush. After all, his Jemma had been attracted to him when they’d first met. Not that he’d known it at the time, or would have even believed it possible until a decade later. But she’d confessed it more than once in the years since. The thought was dizzying, and his heart broke a little for her. Because it already belonged to someone else.

“Look, Jemma—” he began, but she cut him off again.

“Don’t, Fitz. Please. Just don’t.”

He paused for a moment, recalibrating his train of thought. Being jealous of yourself was an awful feeling, one he understood better than she knew. Yet she’d been such a tremendous help to him, offering solutions to problems from her unique perspective, and selflessly shuttling him back and forth to the lab every day without any thought of what was in it for her. It was such a Jemma thing to do. He wanted to tell her how much he appreciated her time and effort, how he couldn’t have gotten this far without her. But he wasn’t sure if that would make it better or worse. Maybe he should just go back to the beginning, focus on the science and leave any inconvenient feelings out of it.

He picked up the spanner he’d been using earlier and held it out to her, a peace offering. “I was only going to ask if you think you can help me figure out what’s wrong with this bloody fusion matrix.”

"Oh." She took the tool and smiled at him, grateful for the return to what had become their normal. Without any further discussion they went back to work.

Two days later they had a prototype ready to test. 

“I think we should run the first test outside,” Fitz suggested, tugging on the external components and tightening nuts and bolts as needed. “In a clear area with enough distance so neither of us will be sucked in.”

“Agreed,” Jemma said, connecting a pair of loose wires. They sparked when they touched each other, causing her to jump back. He was at her side in a flash, but she seemed to be fine. It wasn’t until she continued in a shaky voice that he realized how close they were. “We could use the football pitch. It’s not far from here.”

He stepped away to give her some space and she noticeably relaxed. “Uh. Yeah. Perfect. We’ll come back late tonight, when no one’s around.”

They did just that, packing up the drive and loading it into a nicked shopping trolley under cover of night. The grass was dewy by the time they got there, so they set down a tarp and carefully placed the drive on it. 

In theory, once they activated the drive it would open a portal back to his universe. Fitz had prepared a message in a bottle — an inside joke only his Jemma would get — with a note and the schematics he’d recreated on this side, plus instructions for how to connect the two drives via subsonic frequency. If the portal stayed open long enough to get the message through, she’d know exactly where he was and how to modify the drive to bring him back.

They put as much distance as they could between themselves and the machine, taking a position at the opposite end of the pitch. And then it was time.

“Care to do the honors?” Fitz asked, handing her the remote trigger.

She took it from him, bubbling with excitement. It seemed every version of Jemma shared the thrill of scientific experimentation and discovery. That was a nice thought. “Ready?” she asked. He nodded and smiled. “Steady. Go!”

She pressed the button and the drive glowed, lighting up the sky with a bluish beam that could probably be seen for miles. It shuddered violently and let out a high pitched whine so loud they had to cover their ears. And then . . . nothing else happened.

“Wait. What?” Jemma asked, looking at the remote as if it were the problem.

“I don’t understand. That should have worked,” Fitz said, bolting for the other end of the field, where the drive was already powering down.

She caught up to him and bent over, panting from the exertion. “So, no portal then?”

“No portal,” he said, dejected.

They collapsed into the wet grass, where they sat for a while, shoulders slumped, quietly basking in their failure. Fitz reached into the messenger bag he’d been carrying and pulled out the bottle, rolling it in his palm. 

Jemma put a hand on his arm. “We’ll find a way, Fitz.”

“I know,” he said. “I’m not giving up.”

She bumped his shoulder the same way Jemma used to when she’d give him pep talks at the Academy. “We do have four doctorates between us, after all.” 

A thought suddenly sparked in the back of his mind. 

“Hold on.” He stood and wiped the grass off of Jemma’s dad’s jeans. He always thought better when he could move around. “That’s it! Jemma, you’re brilliant! All we need is more brain power. And I think I know exactly who to bring in.”

Jemma followed him with her eyes as he paced back and forth. It looked like she was watching a tennis match. “Who?”

He stopped and put his hands on his hips, lowering his head to meet her eyes. 

“Me.”


	3. Jemma

**Summary for the Chapter:**

> This time it's Fitz who gets an unexpected visitor.

**Notes for the Chapter:**

> The debt of gratitude I owe to my fantastic friend and beta — the ever-awesome LibbyWeasley — grows with every new thing I write. She continues to be the best!

It had been nearly a week since Fitz disappeared and Jemma was starting to worry. Worry, not doubt, because they’d been through separations and life-and-death situations before and she believed with her whole heart they’d make it through this one too. Somehow. But the Chronicom Hunters were closing in and they had to fix the jump drive and modify it for time travel before time ran out, or else they wouldn’t be able to fix anything at all. Even with Enoch’s help, she didn’t know if she could finish it without her husband by her side.

She was trying to keep her thoughts from spiraling as she worked on the targeting system when, without warning, the drive suddenly came to life. It whirred and lit up like a Christmas tree before her eyes, though she was certain she hadn’t triggered anything. The machine made a dreadful noise and a portal appeared, just like the one that had swallowed up Fitz a week ago. 

She stepped back in shock and called out to the other side of the lab. “Enoch! What’s it doing? It wasn’t even powered up.”

The Chronicom looked up from the workbench where he was making calculations and came to stand next to her, evaluating from a safe distance. “It would seem the jump drive has been activated remotely.”

“Remotely?” That could only mean one thing. “It’s Fitz! It has to be!”

“I estimate a 76 percent chance you are correct. Given that this new portal is highly unstable I would advise caution, but based on what I have learned about the two of you I suspect a warning would be futile.”

Jemma reached for the ring on the chain around her neck. Their plan to stop the Hunters required that they be separated once the jump drive was modified. In preparation for that eventuality, Fitz had given her his ring to hold on to as a reminder that they would always find each other. Neither of them expected they'd be ripped apart again so soon, though.

Now she could almost feel him on the other side, reaching out to her. When nothing came through the portal she knew it was up to her. Enoch was right, there was no point in arguing. Her mind was made up. 

“I’m going in,” she said, and stepped through the portal into a new world. 

Eight sleepless hours later she found herself alone and distraught, facing the dingy front door of a second-floor flat in the east end of London. 

The portal had not brought her to Fitz after all, but to their original target location at King’s College. Which would have been amazing had she arrived in the correct year. It wasn’t even the correct universe, as she’d come to find out. No one was there to greet her. There was hardly anyone around at all, given the late hour. The feeling of certainty that Fitz was waiting for her on the other side collapsed in that moment, and had been steadily fading with every hour she spent in this alternate universe. Even if he was here, how would she find him? She was beginning to regret not having thought it through more before jumping headlong into the abyss. It had become a pattern with her. With both of them, really.

She spent the remainder of the night wandering around the livelier parts of the west end, formulating a plan. She considered looking up her parents. It was what Fitz would have done. He would have sought out her counterpart for help, and he’d have started in Sheffield. But how would she explain herself to them if there was another Jemma in this world already? If there was another Jemma, though, there could be another Fitz too. That was a possibility. She ruled out traveling all the way to Glasgow. She didn’t have the money for a ticket and it was a longshot anyway. Without access to any S.H.I.E.L.D. tech, the internet was her best bet.

She made her way back to the college and waited until the library opened. A cursory internet search showed a few scattered mentions of a Leopold Fitz. He had no social media presence, but there were enough hits to determine that the version of him in this universe had taken a very different path. His name was attached to a number of patents and a business address for an engineering firm in London. The only other mention of him was an obituary for his mother dated September 4, 2006, which read, “She is survived by her son, Leopold James Fitz.” Jemma had to stop reading after that. 

The address had led her to the doorstep where she now stood. It appeared to be more of a residential flat than a business. If it weren’t for a tiny brass plaque with the words “LJF Engineering UK Ltd” on it she would have thought she was in the wrong place.

She knocked a few times and waited. There was a muffled squeak inside, and the sound of creaking floorboards, but no answer. 

She knocked again. This time a voice she knew as well as her own came bellowing through the door, sounding like music to her ears. “Just leave it!” 

She knocked again, more insistently. His annoyed huff was loud enough that she could picture the face he was making along with it.

“I specifically wrote in the instructions _not_ to knock. Just drop off the food and go. Was that too complicated or are you just incredibly—” He opened the door and froze. She could see the wheels turning behind his eyes. She wasn’t at all what he was expecting. Swallowing hard, he completed the sentence with a single word, his voice suddenly hoarse. “Thick?”

“Hello to you too.”

If Jemma hadn’t already been sure, one glance would have convinced her this wasn’t her Fitz. He was dressed in a dark blue cardigan sweater over a grey T-shirt and jeans. He was clean shaven and his hair was longer and curlier than she’d seen it in years. God, how she’d missed those curls. Her fingers twitched with the need to run through them. The cardigan wasn't helping. Or rather, it was. But not in terms of keeping her hands to herself.

“You’re not from the chippy, are you?”

She smiled, which only seemed to make him more uncomfortable. 

“No, I’m not from the chippy.”

“Then who . . . are you?”

“My name is Jemma Simmons. I’m a biochemist. I need your help. May I come in?”

“I don’t take project commissions in person. You can submit a request through the website. That’s what it’s there for.”

He started to close the door, but she stopped it with her hand. “I’m not looking to hire you. I can explain everything if you’ll just let me in.”

“Not interested. Goodbye.”

This time he did manage to shut her out. She stood there biting her thumb, unsure of what to do. This couldn’t be the end of it. She needed to find some other way in. Just as she was starting to formulate an alternate plan, the door opened again.

“Did you say you’re a biochemist?”

An opening, a hope. “I did. Yes.”

“You wouldn’t know anything about biofuels would you?”

“I know a lot about them, actually.”

He deliberated for a moment, then nodded his head as he came to a conclusion. “Okay, you can come in. Just watch your step. And whatever you do, don’t touch anything.”

The last part would have sounded like a dire warning to anyone else. To her, though, his grumpiness was nothing but endearing.

The flat’s interior was like a TARDIS — bigger on the inside. Definitely not as tidy, though. The furniture — a couch that had seen better days, some faded chairs, a coffee table, and several workbenches lined up against the walls — was completely covered with diagrams, machinery, tools, and bits of unfinished projects strewn everywhere. It was hard to tell where his living space ended and the workshop began. In the midst of the apparent disarray she recognized Fitz’s unique style of organized chaos. No matter how messy it looked, he could always find whatever he needed. After years of learning how his mind worked, she usually could too. At least that much seemed to be the same.

He led her over to one of the workbenches lined with stacks of papers filled with scribbled chemical symbols and complicated equations in his handwriting.

“I’m working on a design for a biofuel cell to run a converted diesel engine. I should be getting 100 to 200 more horsepower out of it, but the output isn’t adding up and I don’t know what’s gone wrong.”

She glanced at the papers, not daring to touch them without permission.

“Mind if I— ?”

He made a welcoming gesture. “Have at it.”

She started leafing through the stack, putting together a mental overview of his progress so far. A few things jumped out at her immediately.

“You’re using rubber hosing for the fuel line?”

“Yeah. Why? Is that important?”

“You should consider neoprene or silicone. They’re more—”

“Compatible with biodiesel. Of course. Should have thought of that.”

“And it looks like the specs for the o-rings are about two centimeters off.”

He seemed to take the correction as a personal affront. “They are not.”

“Are so. See? Right here.”

He leaned over her shoulder to see where she was pointing. His chest was nearly pressed against her, and she had to fight her body’s natural instinct to press back. He smelled of machine oil and pencil shavings and something indefinable that reminded her so much of her Fitz it made her heart ache.

“Never mind that. I’m asking for your opinion on the formula. What if I increased the concentration?”

She couldn’t hold back the laugh that came through her nose. “You do _not_ want to do that. Trust me.”

“Are you sure you know what you’re talking about?”

“Ugh, Fitz.” 

In an instant, his guarded expression transformed into a deep frown. He took a step back from her. “What did you say?”

“I’m saying, at this level of compression—”

“No no, after that. You called me Fitz.”

“Well it is your name.”

“It’s my surname. How did you know I go by that? Not Leo or Leopold.”

Damn. It had just slipped out. She was so caught up in the science she’d forgotten who she was talking to. Now she might have just blown her chance with him, and they hadn’t even gotten around to the real reason she was there. Perhaps this was salvageable. No need to panic. 

“It must have been on the website,” she covered lamely. 

“It’s not.” He turned around and headed back to the door, opening it without a glance in her direction. When he continued speaking again, his tone was flat and dismissive. “Sorry, I don’t do government contracts anymore. So you can go back to your bosses at MI-5 or MI-6 or wherever you came from and tell them the answer is no. My compliments on their choice of honey trap, though. Beautiful _and_ smart. Almost had me there.”

“Fitz, wait…” 

“I think we’re done here.” He crossed his arms and leaned against the open door.

“You don’t understand. I’m not with the British government. I’m with S.H.I.E.L.D.”

His eyes snapped back to hers. “What? Strategic Homeland— “

She winced. “You don’t have to say the whole thing.”

“But I thought S.H.I.E.L.D. fell years ago. Back when Hydra tried to take over.”

“It survived. We tend to work more in the shadows now.”

“Oh, as opposed to before? When you were so out in the open?”

“Fair point,” she conceded. “But if you only knew what was at stake, I’m sure—”

“Don’t waste your breath. It’s like I said — I don’t do government contracts. I’m strictly private sector.”

“Oh, for goodness sake. This isn’t about a contract!” Her outburst seemed to startle him into silence. They stood there for a moment, facing each other, both at a loss for words. Finally, she gazed deep into his eyes, so blue and familiar, and continued in a softer tone. “The help I need is of a more . . . personal nature.”

The sound of footsteps on the stairs disrupted the electrostatic charge building between them. A teenage boy with multiple piercings and a mop of black hair in his eyes approached, carrying a plastic bag that smelled like something fried and delicious. Jemma suddenly realized she hadn’t eaten anything since before she’d arrived in this universe. The boy stopped when he reached them, unsure of how to proceed. The instructions probably didn’t say anything about what to do if there were people standing in the doorway when he arrived.

“Just give it to me,” Fitz said, holding his hand out. He must have noticed the way her eyes followed the bag as the delivery boy handed it to him because he added, “Are you hungry?” 

“Famished,” she replied on a loud exhale.

“Might as well stay for lunch,” he said, as if it were the worst sort of inconvenience. “I always order too much food anyway.”

Jemma couldn’t remember the last time she’d had proper fish and chips. They had never tasted so good. Her plate was half empty by the time he returned to the subject of her real purpose for being there.

“So when you say ‘personal,’” he started, pausing to take a sip from a bottle of beer he’d retrieved from his fridge, along with one for her. “What exactly do you mean?”

She decided the simplest explanation was best for now. “I’m looking for someone.”

“Sounds like you need a detective, not an engineer.” He pointed a chip at her, then popped it into his mouth.

“The person I’m searching for will be emitting a particular energy signature. If we can create a device to trace that signature it should lead us right to him.”

“It’s a him then, is it? This person you’re trying to find?”

His attempt at being casual was painfully transparent. She bit her lip to keep from smiling.

“Yes. A fellow S.H.I.E.L.D. agent.” She took a moment, breaking the next part as gently as she could. “My husband, in fact.”

This revelation couldn’t have come as a surprise. She’d caught him eyeing the ring on her left hand earlier. Still, he seemed a little disappointed to have it confirmed.

He took another sip of beer and changed the subject. “I almost joined S.H.I.E.L.D. myself, you know.”

“Really?” She hoped her feigned surprise was convincing. 

“Yeah, yeah. Got accepted to the Academy and everything. Science and Technology Division, obviously. But my mum got sick before I was supposed to leave. And there was only me to take care of her, so . . .”

He trailed off, lowering his gaze and wiping the grease from his hands with a napkin.

“I’m so sorry. That must have been a hard decision for you.”

“Not really. She was always there for me. After my father left and it was just the two of us she made sure I had everything I needed — the best schools, books, materials to build things, a workspace of my own. She didn’t always understand everything I was doing, but she supported me no matter what. So when it was my turn to take care of her, it wasn’t even a question.” 

“She sounds really lovely.”

The Mary Fitz Jemma knew was indeed lovely, as kind and supportive as Fitz had described. Back in their universe she was alive and well, with no idea how close she’d come to losing her son forever. Jemma made a mental note to have Fitz call her as soon as they got back. The thought made her terribly sad for the Fitz of this world, who would never hear her voice again.

He shook his head, as lost in his own thoughts as she was in hers. “I don’t know why I’m telling you all this. I don’t usually talk to this much. To anyone.”

“Maybe that’s why. You just need someone to talk to.”

“Or maybe it’s the beer.” He held up his bottle and downed the rest in one gulp. 

She finished off her own and gave him a reassuring smile. “Maybe so.”

“You want another?” he asked, standing and taking the empty bottle from her.

“Thanks, but no. I should probably keep a clear head.”

“Suppose you’re right. You must be anxious to find him.”

She was, but that wasn’t her primary concern. It was hard enough keeping the two versions of Fitz distinct in her mind when she wasn't under the influence. “You have no idea,” she said. 

Together, they gathered the empty plates and wrappers and carried them to the kitchen. It was the cleanest space in the flat, despite the books and papers that had migrated here from the other rooms. She leaned back against the counter, watching him work as he rinsed the plates and placed them in a drying rack. 

When he was done, he turned to face her, drying his hands on a dishtowel. “What kind of energy signal are we talking about? Because that’s going to be the key element in determining range, power supply, spectrum sensing, and a whole host of other factors.”

She grinned. “Are you saying you’ll help me?”

He tilted his head and looked at her in a way that was so purely Fitz she wanted to cry. “I’m _considering_ it. I still have lots of questions.”

“Of course you do. And I promise I’ll answer them. To the best of my ability.”

The ghost of a smile appeared in the corners of his mouth. “You are an odd bird, Jemma Simmons.”

“So I’ve been told.” 

From somewhere in the living room a phone rang. He didn’t make a move to answer it. She wondered if he’d even heard it. After about a half dozen rings, he seemed to snap out of his daze, irritation once again tensing up his features.

“One second,” he said, holding up a finger before leaving the kitchen to answer the call.

She wasn’t sure whether she should follow or not, but eventually curiosity won out over propriety. She got close enough to hear a female voice on the other end of the line, but couldn’t make out what she was saying. 

Fitz seemed more and more confused as the conversation went on. “Yes. Who is this? . . . Sorry, could you repeat that? . . . But that’s not possible . . . No it isn’t . . . Because it’s just not . . . What do you mean how do I know? . . . Course I have, what’s that got to do with it?”

“What’s going on?” she mouthed, but he turned away.

He put on a fake, overly sweet tone. “Would you mind holding on for a moment please? . . . Great. Thanks so much.” 

“Everything alright?” she asked. Something felt off. Fitz’s face had gone pale and he was staring at her as if he’d seen a ghost.

He pressed the phone into his chest and said in a pinched whisper, “No it’s not bloody alright. You’ve been lying to me since you got here, and I need to know why. Right now. Or we are done.”

“What are you talking about?” Rather than answer her, he raised his eyebrows, awaiting her explanation. “Who’s on the phone, Fitz?”

“She says her name is Jemma Simmons.”

**Notes for the Chapter:**

> Sorry for making you wait for alt!Jemma and alt!Fitz to meet (properly). But there's still one last chapter, and one more point of view (guess who!), to wrap up everything nicely.


	4. Another Fitz

**Summary for the Chapter:**

> What's better than one pair of Fitzsimmons? Two pairs of Fitzsimmonses! It's the reunion you've been waiting for, but not without a little bit of drama. Because Fitzsimmons.

**Notes for the Chapter:**

> At last, we've reached the end! We've got lot of ground to cover here, so buckle up my friends. This one was by far the hardest to write, for reasons which I think will become apparent as you read.
> 
> I can't thank the lovely and talented @libbyweasley enough for helping me tame this beast, for her stellar beta support, and, as always, for being a truly awesome fandom friend.

Fitz didn’t know what to think.

This Jemma Simmons, or whatever her real name was, had come barging into his home with a story about a missing husband and not only had he let her stay, but he’d invited her to share his lunch. Like some sort of besotted schoolboy. He’d even opened up to her about his mum, for chrissakes. He still wasn’t sure why. He didn’t like people as a rule, avoided interacting with them whenever possible. But for some reason, he didn’t dislike her. Not even a little bit. Which was kind of new for him and, much to his surprise, not entirely unpleasant.

And then, with one phone call it had all come crashing down. The woman on the other end of the line had not only introduced herself with the same name, but had the nerve to _argue_ with him about whether that was even possible. He had to grant that highly improbable might be a more accurate term, not that he’d admit it to her. The likelihood that there were two women with that name in the world was somewhat greater than nil, but the odds that both of them would reach out to him individually at almost the exact same time? Astronomical.

Which left him with a conundrum. Which one of them was telling the truth? Or were they both lying? If he had friends, or enemies for that matter, he’d wonder if this was all a setup, part of some elaborate prank. But he wasn’t close enough to anyone to be worth the trouble it would take to cook up something like this. Of course, he also had to consider the remote possibility that they were both telling the truth. The woman on the phone didn’t just share a name with the one standing in his flat, she sounded like her, too. _Exactly_ like her. And she’d asked if he’d heard of the multiverse theory, which would be one possible explanation, if it weren’t complete and utter tosh.

He hadn’t been able to get anything more out of her, though, as the first Jemma had torn the phone out of his hand as soon as he’d told her who was on the other end. She was quick, he had to give her that. Now, the two of them were talking and he was left out of it entirely. But since she had yet to explain anything, he had no qualms about eavesdropping on her end of the conversation.

“You wouldn’t happen to know where my husband is, would you?” she was saying. “I knew it! Would you put him on please? Thank you.”

There was a pause and then he heard an indistinct male voice pick up. Her entire body seemed to vibrate with new energy at the sound. What she said next nearly caused his brain to short circuit.

“Fitz!”

Had he heard right? There was no time to consider the implications of this new piece of information, however, as she continued on at such a rapid clip he had to focus all of his attention on absorbing what he could.

“Okay, that was weird . . . I can imagine . . . Are you alright? . . . Yeah, I'm fine . . . Not sure exactly, sometime last night . . . Ah, that would explain it . . . Yeah, not long . . . No, he’s been a perfect gentleman. I could ask you the same thing . . . Relax, I’m joking . . . I think we can manage that . . . We’ll head straight there . . . Miss you too. Love you . . . together. Yes, we are. See you soon.”

She ended the call with a wistful smile on her face and held the phone out to him, but he didn’t take it. He barely registered the gesture at all. He tried to close his mouth, but found he couldn’t.

“I know you have questions,” she said, all business now. “But we’ve got to get on the road, so I’ll have to explain on the way.”

She started sorting through the tools on his workbench, opening drawers as if she was looking for something. Her impertinence and blatant disregard for his private space brought his consciousness back to the moment.

“Oi! I said don’t touch!” he barked out, slamming the drawers shut after her, one by one. Unfazed by his warning, she simply handed him the tools she’d collected so far and continued her search. Her movements were as sharp and brisk as her thought process, and she outpaced him considerably in both respects. That never happened. People usually had a hard time keeping up with him, not the other way around. “What is this ‘we’ business? I’m not going anywhere with you.”

She finally stopped rifling through his things and looked at him as if she hadn’t heard a word he’d said. “Do you have a car?”

“I don’t drive.”

She nipped at her bottom lip with her teeth. He had no particular feelings about that whatsoever. It was just a nervous habit of hers. No need to avert his eyes. “We can take the train, I suppose. You’ll have to buy the tickets, though. I haven’t any cash and I doubt my credit card works here.”

The tools he’d been holding made a loud clinking sound as he dumped them into a heap on the workbench. He held up both his hands. “Hold on. Back up. First, who are you really? Where are you off to? Was that really your missing husband on the phone? And did I hear you call him Fitz?”

She had the audacity to roll her eyes at him. “We don’t have time for this. Short answers are Dr. Jemma Simmons, agent of S.H.I.E.L.D.; _we_ are going to Birmingham; yes; and yes.”

He decided to let the whole name issue slide, prioritizing the bit that worried him most for the time being. “Birmingham? You’re mad!”

She let out an exasperated sigh, more than ready for the discussion to be over. “My husband is in Sheffield with the other Jemma. They’re going to meet us halfway. Thus, Birmingham. And we need your help, so you’re going too.”

“No, I’m not. You don’t understand.”

“What? What’s the problem?” she asked quickly, her patience reaching its end.

“I don’t _go_ anywhere!” he shouted bitterly. That got her attention. No longer annoyed, she snapped her jaw shut, stunned silent by his outburst. He continued, his voice suddenly low and cracking. “I rarely ever leave this flat. And when I do, it’s only for very short periods of time. I just . . . I feel really uncomfortable out there, all right? Around people.”

“You mean you’re—”

“A shut-in, a hermit, a recluse, call it what you want. The point is, there’s no way I’m going all the way to bloody Birmingham with you. I can’t.”

The last words came out as a fragile plea and he regretted them instantly. He could see the pity in her warm brown eyes, and a fresh wave of embarrassment and self-loathing washed over him. He hadn’t meant to let it get this bad. When he’d first moved to London and started his own engineering firm he used to go out all the time. He would shop at the local market or newsagent’s and make small talk with his neighbors. Sometimes he’d go to the pub for a pint on his own. But he never made any real friends. And over time, he discovered that he felt even more isolated out in public than he did by himself in his flat. Most of the things he needed could be delivered to his door without ever having to speak to anyone, so he went out less and less, until staying in had become a force of habit. It was a hard one to break.

He pinched the bridge of his nose and turned away from her, mostly to hide the unshed tears clouding his vision.

“Oh, Fitz,” she said, the pity now shading her voice too. She put a hand on his shoulder, sending an electric tingle down his arm, which he pretended to ignore. “I’m so sorry. I had no idea. I know I haven’t explained things properly yet, and you have no reason to trust me, but I _promise_ you, if you come with me, you won’t regret it. I’ll be right beside you the whole way, all right? I’ll do all the talking. You won’t have to worry about anything. Please, Fitz.”

He turned around, sniffling a bit, but managing to keep the tears at bay. “But . . . why me?”

“Finding my husband was only the first step in solving a much larger problem. Now that I know where he is, we can move on to step two. And for that we’re going to need you and your engineering genius. If you don’t want to come, I understand. In the past I may have pushed . . . people past their comfort zones, and I’m still not sure whether that was the right thing to do. But in this case I truly believe you were meant to come with me. We need you. I need you.”

He knew she was only flattering him to get what she wanted, yet he still felt his cheeks grow warm at her words. She reached out her hand, wiggling her fingers enticingly, which was doubly unfair, because he’d been trying not to imagine what her hand would feel like in his since the moment she’d stepped into his flat. He’d initially followed that fantasy all the way to her left ring finger, where it terminated a flash of silver. Of course she’d be married. He hoped her husband — this mysterious man who had his name — appreciated what a lucky bastard he was. And now here she was offering Fitz exactly what he’d been telling himself not to want. No, it wasn’t fair at all.

In the end, the decision was easy. Though he’d never met this woman in his life, he had a strange feeling he’d follow her anywhere. Somehow, he suspected, she knew it too. He took the hand she offered as if it were a lifeline. It was a small thing, but it felt monumental.

She rewarded him with a brilliant smile that lit up the dark places inside him. “You’re sure?” He nodded with more certainty than he felt. “Brilliant. Let’s go, then. Oh, and we need to add those tools to your toolbox. Do you have anything else that might come in handy for calibrating a quantum jump drive?”

He’d never heard of such a thing, but she explained the principles of the device as she helped him gather the rest of the tools they might need. According to her, it could open portals to different times and places, even other dimensions. The multiverse that the other Jemma had mentioned was starting make a little more sense. Two Jemmas. Two Fitzes. One pair of them attempting to open a portal to another universe. It was all pointing in a very specific direction, though he felt ridiculous even entertaining the thought. It was like something out of science fiction. He had to stop himself from thinking too hard about what it would mean if it were true. No use getting his hopes up, only to have them shattered again.

The nearest Tube station was a short walk from his building. Still, he had to fight the near constant urge to turn back. Though it wasn’t quite rush hour yet, there were enough people on the street to put him on edge. His body rebelled almost as soon as they stepped outside. His breathing became ragged, and his stomach tried to give up its contents more than once. True to her word, though, Jemma held his clammy hand in hers and murmured calming, reassuring words in his ear the entire way. It helped. She bought the tickets with his credit card and led him to the correct platform. They had to switch trains once at Euston Station, but before he knew it, they were seated across from each other in a semi-private compartment on a northbound train headed for Birmingham.

As soon as they started moving, he looked her in the eye and said, “Okay. We’re officially on our way. This is the part where you tell me everything.”

And so she did.

He listened, chiming in with questions when they occurred to him or asking her to clarify the confusing bits, but mostly he just let her talk until she was finished with her incredible story. By the end of the first hour of their two-hour journey he had a basic understanding of who she was, who her husband was, and how they’d gotten to this world.

“I must say, you’re taking this better than I expected,” she told him, pausing to take a breath as they rolled past Northampton.

In truth, he’d pieced much of it together himself already, though he didn’t dare believe it. She’d filled in the rest of the details, confirming his suspicions. As improbable as the existence of parallel worlds sounded, it fit the evidence better than anything he could come up with. And anyway, he’d find out soon enough whether it was true.

“Thank you for believing me,” she continued. “And for coming along. I know this wasn’t easy for you.”

He smiled softly and shrugged. “What else was I going to do?”

This was, apparently, the wrong thing to say. Her eyes dropped to her lap, where her folded hands tensed. He still had loads more questions, but she seemed to withdraw into herself after that, so he thought it better to wait. They didn’t speak again for the rest of the trip.

As they pulled into the Birmingham New Street station he stood up to retrieve his toolbox from the overhead luggage rack. At the same time, the train slowed to a halt with a jolt, causing him to lose his footing and sending him toppling forward, right into Jemma’s lap. His skin felt suddenly hot and he was sure his face was the shade of a ripe tomato.

“Fitz!” she shouted, launching them both out of the seat.

He was about to apologize profusely for his clumsiness, but quickly realized she wasn’t referring to him. Something outside the train window had caught her eye. It didn’t take long to figure out what it was. Standing on the platform waiting for the train to unload were the two people they had come to meet. He noticed the other Jemma first, the one who belonged in this world. She was dressed more casually, in a T-shirt and jeans, but otherwise looked nearly identical to his traveling companion. And, even more astonishingly, standing right next to her was another Leopold Fitz. His hair was shorter, his face scruffier, and he was dressed like a numpty, but the likeness was uncanny. The few lingering doubts he had about Jemma’s story vanished in that moment. Here was the incontrovertible proof.

He found himself whispering, “Bloody hell,” under his breath, to no one in particular.

The other version of himself was scanning the train cars, probably searching for his wife, when she came running up to him from the side, nearly bowling him over. Fitz’s eyes shot back to the now empty seat across from him in surprise. She must have made a hasty exit from the train while he was looking out the window. He scrambled to get the toolbox and stepped onto the platform just in time to see his counterpart sweep Jemma up into his arms, laughing loudly. She laughed too, a lyrical sound that made his chest feel somehow full and hollow at the same time.

Their lips crashed together in a jubilant kiss that quickly turned into something more heated. Fitz took a few slow steps forward and stopped, torn between wanting to watch and giving them privacy.

After what seemed to him like a very long time, they finally separated, but didn’t break their embrace. Touching foreheads, they stood there breathing in the same air, looking into each other’s eyes, as if carrying on an entire conversation without words.

“Well that’s unsettling,” said the other Jemma. At some point she’d come to stand next to him, but he’d only just now realized it.

“And yet I can’t seem to look away,” he said.

They tilted their heads in unison as their doubles went back to devouring each other ravenously. The Jemma beside him said something else, but he was too distracted to hear.

“Sorry, what?” he said, eyes still focused on the bizarre spectacle before him.

“You must be Fitz,” she said, repeating the words he’d missed earlier.

“Obviously,” he replied absently. He was starting to register the stares of the crowd passing by. Whether it was the very public, very un-English display of affection in the middle of the train station or the unusual sight of what seemed to be two sets of identical twins gathered together, he couldn’t say. He just knew that they were drawing attention. The looks being directed their way felt like dozens of little points of white light burning into his skin, though he seemed to be the only member of their strange quartet to notice.

His hands became so sweaty that the toolbox slid out of his grip and landed on the platform with a loud thunk. The sound seemed to snap the couple out of their private little world and they stopped kissing once again, looking over at their doubles with dazed expressions and matching blushes.

“If you two are done getting reacquainted,” Fitz threw out hotly, wrinkling his nose in distaste, “could we get a move on please? You’re not the only ones who want to get home as soon as possible.”

He knew he sounded testy, but he couldn’t be bothered to care.

“Was I ever this charming?” the other Fitz asked his wife.

Laughing, she put a hand on his chest and spoke into his ear, though it was loud enough for anyone to hear, “Now be nice.”

They smiled at each other like the rest of the world didn’t exist. Fitz felt like he was going to be sick.

The other Jemma spoke up then, her voice a threadier, trembling replica of the one he’d come to know. “The car is this way.”

They left a wake of murmurs and double takes behind them as they made their way out of the station to the street, where Jemma’s car was waiting to take them to . . . christ, he didn’t even know where.

“Fitz can ride up front with me,” Jemma said, and the confusion that followed led the four of them to come to the simultaneous realization that they had a problem.

His Jemma — or rather, the Jemma who had come to his flat, who wasn’t in any way his — was the first one to broach the subject. “This is going to get a bit confusing if we keep calling each other by our first names. We should figure something else out to avoid confusion.”

The other Fitz jumped in, quick to stake his claim. “The two of us can go by our last names. So I’ll be Fitz and she’ll be Simmons. You can be Jemma. And you’re Leo.”

He hated the idea, and the other Fitz clearly knew exactly why. He directed his pleas to the two Jemmas, in the hopes that they’d be more sympathetic to his reasoning. “Why do I have to be Leo? I’m the one from this universe. He should have to change.”

“As S.H.I.E.L.D. agents we’re used to going by our last names,” the Fitz who apparently still got to be Fitz reasoned. “It’s only temporary. Until we perfect the drive and get home. After that you can call yourself whatever the hell you want.”

He didn’t have an argument to beat that, so he was forced to concede.

“Fine, then. I don’t care,” he said, though he cared very much. “Let’s just get going.”

Maybe his next move was petty, but he couldn’t stop himself. He opened the car’s back door and climbed in.

Although the drive to a vacant lot on the outskirts of the city was relatively short, he was glad not to have to put up with the pair of lovebirds canoodling in the back seat the entire way. Jemma — who he had to get used to thinking of as _Simmons_ now — sat next to him and he felt a small, vindictive thrill when she put a comforting hand on his knee. Until she caught her husband’s gaze in the vanity mirror and the two of them started up another wordless conversation with their eyes. Fitz — who was unable to think of himself as anything else — leaned his head against the window glass and watched the scenery go by, bathed in the golden light of dusk.

Jemma parked the car in the empty, dirt-covered lot and popped open the boot as they all climbed out. Fitz took Simmons’ hand and led her around to the back, where he removed the tarp covering the drive with a flourish. It was a clumsy machine, the haste with which it had been put together evident in the shoddy casing and exposed wiring. It might as well have been held together by chewing gum and string. But Simmons cooed over it like a proud mum presented with a portrait in lovingly rendered macaroni art. The two of them started talking over each other in quick, animated fragments as Fitz explained the various components and she asked about the adjustments he’d made. He could immediately identify four — no, five — ways to improve the design, but he kept them to himself.

Glancing over at Jemma, he noticed she was watching the exchange with cool detachment. Almost too cool. Now that he had a chance to really look at her he could see the subtle differences between her and Simmons, beyond their outward appearances. Though they were the exact same chronological age, this version seemed younger and lighter, in a way. Less worn down by the weight of the world. It was like being introduced to a character at the end of a horror movie and then rewinding all the way back to the beginning.

As if feeling his eyes on her, she turned and gave him a shy smile. His stomach did an odd little flip. Searching his brain for something clever to say, something that might impress her, he came up empty. So he didn’t say anything. He realized too late that all he’d had to do was give her a smile in return. Not receiving one, she frowned and turned away again.

Before he could do anything to remedy the situation — not that he had any idea what he’d do if he had the chance — they were all heaving together to get the machine out of the boot. Jemma laid out the tarp while the other Fitz and Simmons positioned the drive on it. He grabbed his toolbox from the back seat and placed it on one corner, then found some pieces of rubble to weigh down the other three. They pulled out work lights and set them up around the perimeter to compensate for the fading daylight as the sun set over the horizon. They did all of this without any direction or a single word spoken among them.

Then they got to work.

The first thing they had to do was troubleshoot what had gone wrong in the last two attempts. The other Fitz and Simmons went over the specifications of the original device, which he learned had been adapted from alien technology, of all things. When they were done, he and Jemma explained what they had done to recreate it. Being part of neither of these build teams, Fitz felt like he didn’t have much to contribute. Then, an idea struck him.

“Have you accounted for quantum entanglement?” he asked. The others fell silent and looked at him with wide, blinking eyes. They didn’t seem to understand what he was getting at, so he elaborated. “There’s two machines, right? What if they’ve somehow become entangled together? So you can’t operate one without the other interfering.”

“But this wasn’t even built yet when the first portal opened,” the other Fitz said.

“Seriously? You really don’t get it?” He received only blank stares.

“Get what?” Jemma asked.

Fitz ran his hands down his face before continuing. “The drive isn’t designed just for spacial distortion, it has the parameters for temporal relocation too, right?”

“Of course!” Simmons exclaimed, finally catching on. “There is no time in the quantum realm. Past, present, future, it’s all the same.”

“Exactly. So it doesn’t matter when this drive was built—” Fitz started.

The other Fitz finished for him. “As long as it exists, or will exist, at some point in time, they could theoretically become entangled.”

“So we need to somehow detangle the two devices?” Jemma asked.

“No, we use it to our advantage,” Simmons said. “Think of them as being tethered across spacetime. All we have to do is isolate that tether and follow it right back to our universe.”

“Should be a simple matter of inverting the amplifier to couple with the superposition rather than the base position.” They were looking at him again, the Jemmas with bright smiles and the other Fitz with a scowl. “It’s merely a bit of advanced quantum engineering. What did they teach you at S.H.I.E.L.D. Academy anyway?”

“It was a multidisciplinary curriculum!” the other Fitz said defensively. The Jemmas laughed in stereo.

They hit their first snag only twenty minutes in. He was working on the power supply with Jemma, who took to engineering surprisingly well for a pathologist, when they got into an argument about the configuration of a circuit.

“No, that’s supposed to connect here,” he scolded, pointing to what he believed to be the correct location.

“No it’s not,” she insisted. “I helped build this thing. I should know where the wires go.”

“Maybe so, but you’re not exactly the expert here are you?”

“And yet I’m telling you, it doesn’t go there. The voltage is off.”

“Just let me do it,” he snapped. Shouldering her out of the way, he reconfigured the wiring the way he thought it should go. He was wrong. As soon as the wires touched, a shower of sparks cascaded out like fireworks, causing him to jump back with a yelp. He filled the air with a dark cloud of curses and then, recovering as best he could, patted down his hair and straightened his cardigan. Rather than admitting defeat, he simply said, “Well that’s just bad design.”

Jemma threw up her hands. “You’re impossible!” She turned to the other Fitz and Simmons, who had the targeting system in pieces at the other end of the tarp, and spoke as if he weren’t right there. “He’s impossible. I can’t do this. Please excuse me.”

“Oh, that’s helpful!” Fitz called out behind her. “Just walk away. Brilliant. That’ll solve everything!”

At some point in time, in another universe, a version of her had fallen in love with a version of him. But that didn’t mean it would be the same for them here. Although she was lovely and brilliant, and he was halfway in love with her already, he had no right to expect anything in return. Nothing in his life so far had indicated he was remotely worthy of such good fortune.

He sunk to the ground, defeated by more than the impossible mechanics of their joint project. Soon he was joined by a female presence, not Jemma as he’d hoped, but Simmons.

“She’ll come around,” she said, rubbing gentle circles on his back. “I think it’s just now starting to sink in that we’re really leaving.”

He nodded at the dirt. “And she’ll be stuck with me.”

Simmons smiled at him with a fondness he didn’t deserve. “Would that be so bad?”

“I don’t know. Ask her. I think I might have buggered things up already.”

She folded her hands and rested her forearms on her knees. “You know, Fitz and I didn’t get along at first either. In fact, I was pretty sure he hated me. It wasn’t until years later that I found out I had it all wrong. He just didn’t know what to say to me.”

He let out a dry laugh. “Sounds familiar.”

“Then trust me when I tell you that you don’t have to try to make an impression. Just be yourself. That’s enough.”

“You can’t know that. You barely know me. I’m not . . . him.”

“I know you had no reason to help me or even believe me when I showed up at your door, but you did. You never asked what was in it for you, you just saw someone in need and you helped, even though it took you miles out of your comfort zone. Because that’s who _you_ are.”

“But she doesn’t . . . she’s not you either.”

“No, she’s not. And I can’t speak for her. Maybe you’re only meant to be friends in this world. We were friends for a long time before we were anything else. Although I wouldn’t want to go back now, I don’t think we properly appreciated what we had back then. How happy we were as partners and best friends. Anyway, my point is, no matter how bad it seems, you haven’t buggered anything up.”

“I don’t know if I even know how to be a friend to anyone, let alone . . . I’ve been on my own for too long.”

“You don’t have to be on your own anymore. Not if you don’t want to. Talk to her. Communication and honesty are always the best approach. I cannot stress that enough. I know it seems scary, but look how far you’ve come in just one day. If it doesn’t work out you can go back to your life in London as if none of this ever happened.”

But he couldn’t do that. There was no going back. Now that he knew about parallel worlds and the existence of Jemma Simmons in this one, nothing would ever be the same. The way he saw it, he had two choices. Say nothing and let her walk out of his life, leaving him to wonder forever what might have been. Or say something and maybe she’d still walk out, but at least he’d have taken a chance. Yesterday it would have been inconceivable, but today he was doing all sorts of things he never thought possible. Why did a machine that could create portals to other dimensions seem so much more plausible than a girl liking him for who he was?

He found Jemma sitting with her back against a brick wall at the other end of the lot. When she heard him approach she wiped her eyes with the heels of her hands and sniffed loudly.

“Jemma.” He slid down the wall and sat next to her.

“If you’ve come to yell at me some more, could you save it for another time? I’m not really in the mood.”

“No, I . . . I don’t want to fight.”

“Okay. Let them know I’ll be back to help soon. I just need a minute.”

“I think they can handle it. They didn’t send me to get you. I came on my own, to apologize. I didn’t listen to you and I lashed out and that wasn’t fair or nice. The truth is, I’ve never been very good with people. I know that’s no excuse, but you are the last person I would ever want to offend, and if I did I’m really sorry.”

“Apology accepted. But . . . why wouldn’t you?”

“Why wouldn’t I what?”

“You said I’m the last person you’d want to offend, but we've only just met. I didn’t think you even liked me. Why would you care about offending me?” He opened his mouth to give her a reason, not knowing what would come out, but she cut him off before he got the chance. “It’s because of her, isn’t it? Did you know you both get the same look on your face when you look at her? It’s kind of disturbing, actually.”

Did he detect a hint of jealousy? The thought made him laugh, a loud, barking laugh straight from his chest. He knew it wasn’t the reaction she was expecting — the puzzled look on her face confirmed it — but couldn’t seem to stop.

“What? What’s so funny?” she demanded, more amused than annoyed.

He twisted his body so he could face her. “It’s just . . . this has to be the most ridiculous scenario in the history of two universes. We’re both resentful of ourselves.”

She laughed too, then. Not as heartily as he had, but it was something. “So you felt it too?”

“I can’t really explain it, but it was like I knew this person was supposed to be in my life as soon as I saw her. Like there was this instant connection.”

“Yes! So weird! You find yourself willing to trust this random stranger, no matter how crazy they sound. And you just know you’d do anything for them. Tell me something. What did you think when you found out her husband was another version of you? Was it easier or harder to take than if it were just some random guy?”

“Um. Harder, I guess.”

“I know, right? It doesn’t make any sense.”

“You know what I think?” he ventured softly. “I think we got our wires crossed, if you’ll pardon the unintended reference to certain recent incidents that would be best forgotten.”

She laughed again, and confidence swelled in his chest. “What are you saying exactly?”

“I’m saying I don’t think it was supposed to be us and them. I think it’s supposed to be you and me.”

As soon as he said the words, he knew they were true. He had never believed in destiny or soulmates or anything so unscientific, but then he hadn’t believed in the existence of parallel universes before either. They sat there in silence for a long time, looking for evidence of this new revelation in each other’s eyes and finding it as obvious as the stars twinkling in the early night sky.

She was the first to break the spell. “Could we start over? We never did get a proper introduction.”

“Hmm. I guess we didn’t.” He put out his hand for her to shake. “I’m Leopold Fitz. Please, _please_, call me Fitz.”

She shook his hand once, but didn’t let go. “It’s nice to meet you, Fitz. I’m Jemma Simmons. You can call me Jemma.”

He felt weightless, as if her hand was the only thing keeping him from floating away. It didn’t last long, though. Their little bubble was burst by the sound of the other Fitz and Simmons approaching rapidly.

“Good news!” Simmons announced. “We’ve completed the modifications. The drive should work properly now, thanks to Leo’s clever breakthrough. See, I told you we’d need you.”

She winked and he had to stifle a double cringe, at the compliment and the use of his first name.

“We’ll need to run a test first,” the other Fitz cautioned. “But we believe it’s good to go.”

“So what are we waiting for?” Jemma said. “Let’s get you home.”

She almost sounded anxious for them to leave. Interesting.

The first test was a success. He didn’t miss the fact that Jemma had turned to hug him first as soon as they’d done it, or the way she lingered a little before pulling away. The other two didn’t notice any of this, as their chaste congratulatory kiss had turned into another enthusiastic snogging session. How did they ever get anything done in the lab? This time, he and Jemma didn’t care to watch them go at it. Instead, they looked at each other. She rolled her eyes, but her cheeks were unmistakably and adorably pink.

Soon the time came to say goodbye.

He wished the other Fitz luck and was surprised to find that he meant it. Simmons hugged him and told him to remember what she’d said. As if he could ever forget. Then the couple faced each other, holding hands, as he and Jemma engaged the drive. There was a flash of light and a high-pitched whining sound and then they were gone.

“Well, this has got to be the weirdest day ever,” Fitz — now the one and only in this universe — said, rubbing his forehead.

“What are you going to do now? Back to London?”

“I don’t know. I’m suddenly feeling really hungry.“

“Me too. Now that you mention it.”

He smiled as an idea formed. The way she was looking at him made him feel dangerously brave. “Do you want to get some dinner?”

“Sure. We can grab a bite somewhere in town.”

She didn’t seem to understand what he was getting at, so he clarified. “I mean, can I take you out to dinner? Someplace . . . nice?”

“Oh.” She paused for a minute, then continued, softer. “Yes. I’d like that.”

They walked to her car, hand in hand. Just before they reached it, he brought them to a stop. He turned to face her and took her other hand as well, a mirror image of the way Fitz and Simmons had stood together before they disappeared.

“Fitz?”

“I just want to try something,” he said, licking his lips. Her eyes flicked down for an instant, before finding his gaze once more. In the bright, artificial glow of the work lights she looked like something out of a dream. He leaned down slowly, for once letting himself be drawn in rather than resisting the pull. Stopping halfway, he waited to see if she would make up the distance.

She did.

**Author's Note:**

> Thanks for reading. Feel free to come shout at me over on tumbler, where I'm @blancasplayground!


End file.
